PROBLEM: The effect of LSD on the recognition and recall of
verbal and visual stimuli.

MATERIAL: 12 non-psychotic adults (6 F, 6 M). Age range 21-33.

METH0D: 5 visual and 4 auditory tests were used, containing
stimtuli of varying degrees of familiarity. All 12 subjects
were tested three times and 8 were tested four times. At the
first session placebo was given, at the 2nd 50 ug LSD, at the third lO0 ug LSD, at the fourth placebo. There was an interval
of at least 1 week between the sessions. Tests carried out
approx. 1 hour after administration of drug or placebo.

RESULTS: lO0 ug LSD significantly impaired recognition or
recall in 6 of 9 tests, as compared with the performance after
placebo. 50 ug LSD produced an insignificant effect on recall
and recognition. Only sentence recall showed significant
improvement from pre-LSD to post-LSD placebo sessions. However,
all tests showed some improvement.